911

After a hard, hot run, the coolant keeps on dumping out of the top-up 'reservoir' by the battery.
I keep on re-filling with water via the header tank to keep the motor cool.
Questions:
Why does this happen?
Is there a way to avoid an air lock in the system?

When it happens the top radiator hose is hot, and the bottom hose is cold.
Eventually, there are bubbles gurgling in the top-up reservoir!

Any ideas guys?

911

drb5

iTrader: (4)

defo got an air block somewhere m8! give me a sec and i've have a bigger post up how to cure it....

drb5

iTrader: (4)

take the cap of the reservoir and also the pipe closest to bulkhead on the reservoir. squeeze the fat top coolant pipe at left hand side of radiator and keep it squeezed. now put your thumb over the removed pipe at reservoir and let go of the fat coolant pipe. this should draw the coolant down through the reservoir into the radiator. keep topping up and doing this untill no more wayer can be added. then replace the wee pipe, put cap back on and try. remember and do this when the coolant is cool though

ROO4NFG

Sounds like a circulation prob poss radiator no flow, so no hot water entering the rad there for no way of engine or cooling fans to cool engine, if i was u i would check the thermotate is opening first tho.
hope this may help.
cheers jon

albob

could be a blown head gasket... the escaping gases force your coolant out of the of the system into the overflow reservoir - at least this is what happened to two of my cars !!

alan

Jay m A

iTrader: (2)

Interesting. I have a suspected head gasket failure and have suffered the same thing. My coolent hose at the bottom of the rad is lukewarm too. Did this happen with yours Albob?

And could an air block cause a head gasket failure?

Pavlo

sounds like the stat might be dead.

Hol

iTrader: (1)

Yup, this same thing happened to my mates 97WRX.

New gasket fitted and no more problems.

bruce

iTrader: (5)

Same thing happened to my MY97WRX also, after a hard run take the cap of the overflow bottle by the battery and rev the engine, I could see lots of small bubbles appearing when the gaskets had failed.

911

Thanks for the ideas!
I will try the easy ones first, pipes/air lock etc. My dealer recons this is the problem.
Will fit a new stat while i'm down there. The coolant is fine under hard road driving, just does this when hill climbed for 50 seconds!
I feel (hope) it is the air lock as i get a steady flow of BIG air bubbles coming into the battery side top-up tube when the engine is switch off for, about 10 minutes.
thanks again.
911

albob

Jay m a
cant say about the luke warm bottom hose - didnt notice on mine!
But yours sounds like it could well be an air lock in the cooling system.
Wouldn't have thought it cud cause the head gasket to blow tho'...........


alan

siwrx

I had exactly the same problem with mine and went through all the airlock, thermostat steps etc. It actually ended up being the water pump which had gone funny and was only working some of the time. Check the cheap things first though

911

Stat might arrive tomorrow, so will fit it as a precaution, drain the system and bleed it as above, which is very close to the Dealer trick in method.
I think the water pump is a real sod of a job, and I hill climb again in 2 weeks time, so will keep to the simple stuff.
Doubt that the head(s) have gone as the car runs clean and it goes like stink.
911

magnet

put the heater on hot, if it blows hot then cold and then mostly cold, then it may be an airlock.

mines just boiled up all it coolent for no reason, seems ok now but has developed a stutter at 3k.

911

Right. I thought I would try the trick to remove the air lock from the system. Fed-up of queeeeeezing the top/bottom hoses with the rearmost of the small tubes on top of the header tank removed, all seems to do nothing at all.
I presume it is NOT the turbo cooling pipe you remove from the header(?).

What I have tried is:

1 remove the rearmost small tube off the top of the header tank. this tube runs to the top of the left hand end of the rad, adjacent to the large top hose.
2 Filled the header to the top with water/antifreeze.Left the pressure cap off.
3 squeeze the top hose flat, put my thumb over the end of the small hose and release the top hose. Repeatedly. Effect? Bugger all. Level in header the same.
4 Do the same with the lower hose on the bottom right of the rad. Effect? as above!

I can hear the coolant swishing around, but i think the rad is full.
Stat arrives tomorrow I hope, so will drain, fit new stat and refill.

Any tips as to re-filling from 'dry'?

This cannot be hard as the factory wouldn't fool around like this!

Help.
911

drb5

iTrader: (4)

yep. radiator must be full then dood shame it never helped

911

But thanks for your help!
Maybe it is the stat after all.
911

CustomScoobyIOM

Could be stat. Had alot of issues with my STI3.

Tried everything listed here:
- Stat replaced
- Coolant drained properly etc. etc.

Have you tried to take the rad out? 2 bolts and lift. Get all the water out that way and flush through.

Otherwise head gasket. What mine was. Replaced and fine!

Car overheated after long drives, but just filled with water and was fine! Same as yours. Check to see if the head gasket is crumbling at all. Powder around it.

Cheers

Pavlo

If the bottom hose is cold when the top is hot, the coolant isn't flowing. If there is little or no air in the system, it leaves only the stat. The coolant system is generally vary resistant to airlocks as the air naturally goes to the header tank relatively easily.

Paul

siwrx

Although when it gets them it is a right **** to get them out. I had the car running for 40 mins to clear the locks out after changing my water pump.

What subaru told me to do was take the cap off the header tank and hold the car at 3-4000 rpm for about a minute then when u ease off loads of water will **** out the top as the air comes out. Refill and repeat until its full and all pipes are hot....... oh and unplug the bloody fans! they kept cooling the engine down too much for the stat to open. Just reattache them once youre done

911

Thanks for all this help!

New Scooby genuine stat just arrived in post today.

Pavlo, the rad condition is EXACTLY as you say, hot top hose, stone cold bottom. I think I will drain the system, fit the stat/gasket, remove the rad and back flush, and start all over again.

I think I last did this way back in the 70's! (Triumph Spitfire!)

Thanks as ever everyone,
911

911

Put it all back together again and checked the original stat in boiling water, opened just before water boiled up.(therefore ok?)
Have just run the engine till the fans came on. During the 'warm-up' had large bubbles coming up in the top-up tube, stopped after 5 mins, guess this was the trapped air in the system.
no high temp gauge reading etc yet, hope its all done now.
911

911

After reading the news about the Group B tube headers, not sure if they are a good buy.
So! Does anyone make tube headers that keep the Scooby Sound?
911

drb5

iTrader: (4)

surely the bottom hose won't be hot till the water does start to circulate though when the stat opens?

911

DRB:
That is right, but the bottom hose was cold even when the temp gauge was sky high!
Presumably because there was no water in the system.
911

drb5

iTrader: (4)

ahhhhhhhhh, that'll make sense then. i apologise if you typed this and i never picked up on it otherwise, the stat has gotta be the problem.


glad you got it sorted m8

911

Still in trouble!
Changed the stat, filled the system, went for a 'hot' blast for 3 miles after warming the engine for 5 miles.
Pulled over, engine temp perfect, but side of car splattered in coolant.
On tick-over bubbles in top-up filler.......
Drove home slowly, switched on heater full blast and watched temp gauge plummet (as you would ecpect) and temp gauge settled to normal again.

I think the other guys might be right, blown head gasket(s)!

ANY OTHER IDEAS PLEASE? Damned if i can think of any other reasons.

On tick-over ther is NO smoke, steam etc coming from the exhaust, at revs nothing either. Can only conclude that the cylinder gasses leak into the water way and pressurise the water tract. BUT, why would those gasses not just vent to the blow-off tube on the Header tank and off to atmosphere.

Where does the large tube off the base of top up (by the battery) go off to when it goes into the inner wing? To the heater matrix? Must connect to something otherwise the water would blow off through that hose...bloody hell!

My racing season could suddenly be cut short.

911

siwrx

if there are no signs of a leak it sounds like the water isnt circulating same as mine wasnt. Might take a while to get hte air out, you could drive it for a few miles with no cap on the header to force the air out

Rally

I had similar symptoms - red hot top hose, cold or luke warm bottom hose and it used to boil coolant and spit it out after 5 mins of normal driving.
Mine went through 2 std rads (end tanks went) so I fitted a gpN alloy one, no change, although it could not blow this one. I refilled coolant using drb5's method listed previously in this thread. It then started blowing coolant past jubilee clips on top hose, so I fitted Samco ones and did em up tight and went on search of the problem.

I was told it was probably head gasket, but as a final thing to change go for thermostat.
I removed the stat altogether as it is summer now and no more problems.

Maybe when I get around to fitting my new stat the problem will re-appear, if so I reccon it must be coolant system getting pressurised by gasses coming past head gasket, but car is running great at moment so I will put that day off.

911

Thanks again for the info.
Will try bleeding as DB5 (again) but with the heater full 'on' just incase the lock is there. As said before, stat is new and no change. Never thought to remove it altogether, good easy next step.
It seems to chuck it out only when blasting it hard, ie 7000+ rpm.
I too will leave it all until Xmas when many engine mods are planned to keep with the bloody EVO's on the hills!
911